Buienradar MCP Server

Instructions

Implementation Reference

• server.py:41-47 (handler)

  Main handler function implementing the tool logic: fetches raw precipitation data via API and formats it for output.

  async def get_precipitation_for(lat: float, lon: float) -> str:
      """Fetches precipitation data for the next 2 hours from Buienradar."""
      data = await make_request(format_url(lat, lon))
      if not data:
          return "Could not get precipitation data."
      
      return format_response(data)

• server.py:40-40 (registration)

  Registers the tool using FastMCP's @mcp.tool() decorator, which uses the function name 'get_precipitation_for'.

  @mcp.tool()

• server.py:11-14 (helper)

  Helper function to construct the Buienradar API URL from latitude and longitude.

  def format_url(lat: float, lon: float) -> str:
      lat = round(lat, 2)
      lon = round(lon, 2)
      return f"https://gadgets.buienradar.nl/data/raintext/?lat={lat}&lon={lon}"

• server.py:17-26 (helper)

  Async helper to perform HTTP GET request to the API and return raw text or None on error.

  async def make_request(url) -> str | None:
      headers = {"User-Agent": USER_AGENT}
      try:
          async with httpx.AsyncClient() as client:
              response = await client.get(url, headers=headers, timeout=30)
              response.raise_for_status()
      except Exception as e:
          return None
  
      return response.text

• server.py:29-37 (helper)

  Helper to parse raw API response and convert to formatted CSV-like string with mm per hour.

  def format_response(data: str) -> str:
      result = ["time, mm per hour"]
      for line in data.strip().split('\n'):
          intensity, time = line.split("|")
          intensity = int(intensity)
          mm_per_hour = round(10 ** ((intensity - 109) / 32), 1)
          result.append(f"{time}, {mm_per_hour}")
  
      return "\n".join(result)